1. Field of the Invention
The present invention relates to a control device for machines, such as working machines, industrial machines, and robots, and more particularly, to a machine control device including a display operation device which is detachable from a machine control device body.
2. Description of the Related Art
In general, a display operation device of a machine control device is attached to a machine control panel. However, when the display operation device is fixed to the machine control panel, the operation position of an operator is also fixed. For example, in the case of a large working machine, the machine needs to be operated in various places by the operator. When the position of the display operation device is also fixed, the operation position is fixed, which results in low operability.
In order to improve the operability, a method has been proposed in which a display operation device 1 can be separated from a machine control unit body 2, the operator of a machine manually operates an operation unit 6, such as a keyboard, and display information signals or operational signals are wirelessly transmitted between the display operation device 1 and the machine control unit body 2 through a display-operation-device-side transceiver 8A and a control-unit-side transceiver 8B, as illustrated in FIG. 5.
In this case, the display operation device 1 includes a charger 5 including a charging circuit and a rechargeable battery. The rechargeable battery of the charger 5 can be charged. When the display operation device 1 is not operated or when it can be operated in the vicinity of the machine control unit body 2, a connector 7 which is provided in the display operation device 1 is connected to the machine control unit body 2 by a connection cable 4 and a power supply 3 connected to the machine control unit body 2 is connected to the charger 5 of the display operation device 1 by wire.
When the connection cable 4 is disconnected from the display operation device 1 and the display operation device 1 is separated from the machine control unit body 2 and is then operated, the display operation device 1 is operated by power from the charged battery and wirelessly transmits and receives display information or operational information. The machine control unit body 2 includes a machine control circuit 9 having the function of a machine control device. The machine control circuit 9 is driven by power supplied from a power supply. The power consumed by the display operation device 1 includes power for a display operation and a wireless communication operation of the display operation device 1.
Japanese Patent Application Laid-Open No. 6-95772 discloses a technique in which, in an electronic apparatus which includes a main body and a slave machine, an electrode of the main body is connected to an electrode of the slave machine by a connector and power is supplied. In a case in which the electronic apparatus is used in a bad environment in which the air is filled with a cutting fluid mist, when the connection cable is disconnected, the connector needs to have a waterproof structure, such as a cover or a cap with a packing. However, even when the waterproof structure is used, operability is reduced due to frequent detachment of the connection cable. In particular, in the structure using the cover, there is a concern that the failure rate of a movable part will increase and reliability will be reduced. In the structure using the cap, there is a concern that the cap will be lost. Therefore, a spare cap is needed. Even when measures to the cutting fluid are taken, it is difficult to provide complete solutions to the cutting fluid mist which fills up the air. A very small amount of infiltrated cutting fluid rusts the connector. For the disconnected connection cable, a connector portion needs to be covered such that the cutting fluid is not infiltrated into the connector portion, the entire cable needs to be put into a bag, or the cable needs to be kept in the place where it is not affected by the cutting fluid.
Japanese Patent Application Laid-Open No. 2011-82653 and Japanese Patent Application Laid-Open No. 2006-5978 disclose a technique which wirelessly supplies power to an apparatus. In this technique, since power is wirelessly supplied, a power supply connector is not needed. Therefore, a connection portion does not need to be proof against, for example, a cutting fluid. However, in the technique disclosed in Japanese Patent Application Laid-Open No. 2011-82653, the control unit controls the turning on and off of a power supply unit that wirelessly supplies power. Therefore, there is a concern that a control operation will be complicated. In the technique disclosed in Japanese Patent Application Laid-Open No. 2006-5978, the power supply unit which wirelessly supplies power operates constantly. Therefore, the power supply unit continuously supplies power even at the distance at which the supply of power is not available. As a result, there is a concern that efficiency will be reduced.